Anime characters already have impossible physiques, not to mention supernatural powers in many cases. You don't have to match them to cosplay as them. Yes, there are the trolls out there, just like on forums, who intentionally cosplay badly to make cosplay look bad. But even if your waist isn't the 12" that the anime seems to show, or your shoulders aren't 3' across, or you lack the rugged chin that could cut glass, you can still have fun dressing up as a character you find interesting.